Help choosing a spring rate for the GK

[Highway_Glider]

Hi guys.

Winter is upon us and that of course mean fixing the little bugs before spring.

Last summer I did The Labrador Highway.

I know. Pictures or it didn't happen:








Now. I am not exactly sure why but the front fork decided to vomit all it's oil. Yes, both sides.




My search in the archives gives me Sonic as the better choice.

Almost there.

There are no direct choices for the GS1100GK. The closest is the GS1100.....Different fork, certainly a heavier bike. And I am at a lost for choosing a rate. There are five to choose from.

Any input will be appreciated.

Yes, I did write Sonic for their advice. But I prefer one from the GSR.

Thanks,


Daniel

[Nessism]

Sonic has a spring rate calculator. Did you go through that?

Doesn't the GK have the larger 41mm fork?

[Highway_Glider]

Hello Nessism. Been a while. Hope all is well.

Yes, there is a calculator. But It as only the rider's weight. It presumes the bike to be the GS1100.
And yes, again, the larger forks.

Maybe the diameter doesn't matter, don't know, but the weight distribution is certainly different than If I tell the calculator that I weigh another 100lb.

The fairing is directly on the wheel and the cases are often loaded....


Daniel

EDIT

I revisited the calculator and It does ask for the bike weight.

I'll fudge something I guess.

[Highway_Glider]

Just revisited the calculator and assuming the owner manual wet weight (639lbs) and 100lb of cargo I get a rate of 1.1kg/mm.
If I put more weight I get a spring they don't have.

Just getting their larger spring just doesn't sound optimal....

[Nessism]

Since the forks are 41mm, good chance you can get 1.2 springs if that's what you need. Don't think you should use GS1100 springs because those forks are skinnier than yours. You may need to email Sonic for more details. The Sonic springs owner is a member here so you could PM him as well but I'd just use the email contact they have. http://www.thegsresources.com/_forum...97-RichDesmond

[Redman]

Yes, GK has 41mm forks. (regular GS1100G and most others are 38 I think).

I got Progressive (brand) springs a few years ago. I dont recall having to use any calculator, so must have had a specific set listed for GK.

.

[Highway_Glider]

Yes, GK has 41mm forks. (regular GS1100G and most others are 38 I think).

I got Progressive (brand) springs a few years ago. I dont recall having to use any calculator, so must have had a specific set listed for GK.

.

Since the forks are 41mm, good chance you can get 1.2 springs if that's what you need. Don't think you should use GS1100 springs because those forks are skinnier than yours. You may need to email Sonic for more details. The Sonic springs owner is a member here so you could PM him as well but I'd just use the email contact they have. http://www.thegsresources.com/_forum...97-RichDesmond

Hello Redman. Long time no speak.

Yes, Would prefer something specific than something 'Make do".

Just checked progressive and yes they have one specific for the GK.

Of course for all I know it's the same as for the Regular GS1100. But at least it's recommended.

They are 12$ more. No clue on the shipping cost.

I will wait and see the reply from Sonic.

[Nessism]

Be careful if using Progressive. They use the same springs for a lot of different applications. For example, they recommend the same springs for bikes weighing 100 lbs different from one another. With Sonic springs you get to pick the spring rate you desire for your application. There are no "GK springs", just springs appropriate for a GK.

[Steve]

Well, I have a "Junior" GK, does that count?

Yeah, I have the skinny 37mm fork tubes, but that won't affect the rate. Consider that the GS850G was heavier than the GS1100G. Only 10 or 15 pounds, but still heavier. I have added GK luggage at the rear and a Pacifico AERO fairing on the front. Not sure how the weight of the AERO compares with the GK fairing, but mine is about 30 pounds, so overall weight might be similar.

I went with the 1.1 Sonic springs and 10w fork oil. The ride is absolutely SUPERB.

I will be rebuilding my KONI shocks at the rear and adding slightly stiffer springs to them, hope the ride at the rear is as good as the front.

Contact Rich Desmond to see if there are springs for the 41mm forks, then choose the 1.1 rate, I think you will enjoy it.

.

[Highway_Glider]

Be careful if using Progressive. They use the same springs for a lot of different applications. For example, they recommend the same springs for bikes weighing 100 lbs different from one another. With Sonic springs you get to pick the spring rate you desire for your application. There are no "GK springs", just springs appropriate for a GK.

Thank you Nessism.

Well, I have a "Junior" GK, does that count?

Yeah, I have the skinny 37mm fork tubes, but that won't affect the rate. Consider that the GS850G was heavier than the GS1100G. Only 10 or 15 pounds, but still heavier. I have added GK luggage at the rear and a Pacifico AERO fairing on the front. Not sure how the weight of the AERO compares with the GK fairing, but mine is about 30 pounds, so overall weight might be similar.

I went with the 1.1 Sonic springs and 10w fork oil. The ride is absolutely SUPERB.

I will be rebuilding my KONI shocks at the rear and adding slightly stiffer springs to them, hope the ride at the rear is as good as the front.

Contact Rich Desmond to see if there are springs for the 41mm forks, then choose the 1.1 rate, I think you will enjoy it.

.

Yes, your opinion always count Steve.

I already wrote Sonic on their website email. I will wait a few days then write Rich directly.

The numbers I get from the net puts the GK at 80lbs over the 1100G. 40 lbs over the stock 850G. So Junior is probably close.

When playing with the calculator. I get 1.1 rate for 100 lbs of cargo. 1.2 for 150 lbs. Probably closer to closer to real life that.

But the site doesn't have over 1.1 (For the 1100 anyway) maybe it will involve one of those PVC preload spacers that you keep reading about.

As for the diameter. They will tell me what they have.

Pretty sure they have dealt with the GK before.

[Nessism]

Spacers don't increase spring rate, just preload. You can expect to install the springs and then add spacers to get the preload you desire which affects ride height.

The Bandit 1200 springs (or similar) are probably the ones you need.. Rich will hook you up.

[Steve]

Spacers don't increase spring rate, just preload.

And increased preload does NOT increase the spring rate, it only raises the ride height.

Picture this: (all hypothetical numbers here) Let's say that with whatever spring rate you have, the weight of the front of the bike will compress the springs two inches. You take the guts out of the forks and find that you have springs and a spacer that is 5 inches long. If you install a new spacer that is 6 inches long, the only thing you are going to do is to raise the front of the bike one inch. The springs are still compressed just as much as they were before, because the springs have not changed and the weight has not changed, but the longer spacer holds the bike a little bit higher.

By the way, the same concept works at the rear, too. Cranking up the preload doesn't make the springs any stiffer, it only lets the bike ride higher. The exception is that if you only compress the springs about half an inch when you get on the bike, but you can add an inch of preload. In that case, you will be riding a rigid rear end until you add enough weight to start to move the spring. As long as the preload you add is less than the amount you have compressed the spring, the ride stiffness won't change.

.

[Highway_Glider]

Spacers don't increase spring rate, just preload. You can expect to install the springs and then add spacers to get the preload you desire which affects ride height.

The Bandit 1200 springs (or similar) are probably the ones you need.. Rich will hook you up.

And increased preload does NOT increase the spring rate, it only raises the ride height.


Picture this: (all hypothetical numbers here) Let's say that with whatever spring rate you have, the weight of the front of the bike will compress the springs two inches. You take the guts out of the forks and find that you have springs and a spacer that is 5 inches long. If you install a new spacer that is 6 inches long, the only thing you are going to do is to raise the front of the bike one inch. The springs are still compressed just as much as they were before, because the springs have not changed and the weight has not changed, but the longer spacer holds the bike a little bit higher.

By the way, the same concept works at the rear, too. Cranking up the preload doesn't make the springs any stiffer, it only lets the bike ride higher. The exception is that if you only compress the springs about half an inch when you get on the bike, but you can add an inch of preload. In that case, you will be riding a rigid rear end until you add enough weight to start to move the spring. As long as the preload you add is less than the amount you have compressed the spring, the ride stiffness won't change.

.

Make sense.

Now that I was pointed that way.

Thank you.

[Highway_Glider]

Last update.

Rich as replied. A few times.

1. The GK as been added to the bike choices.
2. The spring choices take into account the diameter of the tubes.
3. He says to use the calculator without cargo. Which gives me 1.0
4. He recommends 1.1Kg/mm. Sounds good to me.
5. Springs ordered.

Cost is 85$USD + 32$USD shipping = 117$USD = OUCH in CDN.

Thank you one and all.

[Steve]

4. He recommends 1.1Kg/mm. Sounds good to me.
5. Springs ordered.

Don't forget the 10w oil.

.